T-mount to Sony E adapter compatibility

T-mount is the one entry in this matrix that is not really a camera mount at all. It is a lens-side interface — the M42 × 0.75 thread Tamron introduced in 1957 and standardised as T-2 in 1962 — with a fixed 55 mm spacing from the thread shoulder to the focal plane. The lens carries no bayonet of its own; instead it screws into a body-specific T-X adapter ring, and it is that ring which carries the camera mount. For a Sony mirrorless body you fit a T-Sony-E ring: the lens threads into the front, the E bayonet sits on the back, and because Sony E's flange is only 18 mm the ring is built as a roughly 37 mm tube that makes up the difference. That leaves a full 37.0 mm of clearance, so infinity focus is never in doubt — the optics always sit at their designed 55 mm regardless of which body the ring adapts to. The appeal is exactly that one-lens-many-bodies design: buy the glass once, change the cheap ring when you change systems.

What you actually mount tells the story, because the catalogue here is all long glass — that is what T-mount has always been for. The Vivitar 500 mm f/8 Mirror and the Samyang 800 mm f/8 Mirror MC are catadioptric (mirror) lenses, astonishingly compact for their reach because the light path folds back on itself, and the Soligor 400 mm f/6.3 Tele is a conventional refractive long lens. None of them autofocuses; all three were built as budget reach for wildlife, the moon and the sun. Sony E is the natural destination because no system has a larger installed base of bodies a vintage-glass or astrophotography shooter is likely to already own — from a full-frame A7 IV or A1 down to an APS-C A6700 or ZV-E10 — and a generic mechanical T-Sony-E ring from Fotodiox, K&F Concept, Gobe or any number of vendors costs less than a memory card.

The verdict reads Mechanical · MF · no IS · Ap. ring, and every term is honest for this glass — with one nuance the badge cannot show. Focus is manual, set on the lens barrel and confirmed through the body's focus peaking and magnified view, because there are no electrical contacts anywhere in a T-mount lens or its ring. 'Ap. ring' is true of the refractive Soligor 400 mm f/6.3, which has a real manual diaphragm — but it is not true of the two mirror lenses. A catadioptric design has no iris at all: the Vivitar 500 mm and Samyang 800 mm are fixed at f/8, so you control exposure with shutter, ISO and screw-in ND filters, and you live with the signature ring-shaped 'donut' highlights a mirror lens renders out of focus. None of the three passes EXIF, electronic aperture or stabilisation data to the body.

Stabilisation is still available, but you have to ask for it. Sony's in-body IBIS works with a fully manual lens, yet a dumb T-X ring tells the body nothing, so you must open the SteadyShot 'non-native lens' setting and enter the focal length by hand — 500 mm for the Vivitar, 800 mm for the Samyang — before the sensor-shift system will engage, and even then IBIS only tames so much shake at those lengths, so a monopod or tripod stays part of the kit. Image circle is the easy part: all three lenses cover full-frame, so they shoot clean on a full-frame A7, A7R, A7S or A1, while an APS-C body (A6700, ZV-E10, FX30) reads the centre and applies its 1.5× crop — turning the 500 mm into a 750 mm-equivalent and the 800 mm into a 1200 mm-equivalent reach monster with no vignetting.

The honest summary: T-mount → Sony E is the budget-reach and amateur-astronomy route, not a precision cine or AF path. Fit a generic mechanical T-Sony-E ring, focus by hand on the EVF, accept fixed f/8 on the Vivitar and Samyang mirror lenses (and their donut bokeh), use the Soligor's aperture ring when you want a conventional rendering, and register the focal length in SteadyShot so IBIS helps at the long end. And because T-mount is the de-facto standard for astronomy optics, the very same T-Sony-E ring threads onto a telescope's focuser for prime-focus lunar, solar and deep-sky work — so one inexpensive ring serves both your mirror lenses and your scope on the body you already own.